Rosin compounds of improved color and stability



United States Patent Of] ice 3,423,389 Patented Jan. 21, 1969 14 ClaimsABSTRACT OF THE DISCLOSURE The color and color retention of tall oils,tall oil fractions, rosins and rosin compounds are improved by addingabout 0.01% to 1% of a phenol sulfide monomer or polymer and heating at180-350 C., preferably under a blanket of nitrogen, until products ofbetter color characteristics are obtained.

This is a continuation in part of two copending applications of CharlesG. Wheelus, Serial Nos. 579,851 and 579,819, filed on September 16,1966.

Application Serial No. 579,851 is a continuation-in-part of Serial No.496,660, filed October 15, 1965, which became abandoned after thecontinuation-in-part application was filed.

Application Serial No. 579,819 is a continuation-in-part of Serial No.496,667, filed on October 15, 1965 and Serial No. 560,866 filed June 27,1966, both now abandoned.

This invention relates to methods for improving the color and colorretention of tall oil, tall oil fractions predominating in fatty acids,tall oil fractions predominating in rosin acids, rosins and rosincompounds including tall oil rosin, wood rosin and gum rosin andcompounds thereof. The invention includes methods wherein thesematerials are subjected to heat treatments at bleaching temperatureswithin the range of about 180 C. to about 350 C. in the presence ofsmall quantities of a particu larly defined class of phenol sulfidebleaching and color stabilizing agents and for times such thatimprovements in color characteristics are obtained. The invention alsoincludes the improved tall oils, tall oil fractions, rosins and rosincompounds obtained by these methods, all of which are characterized by alighter color and an enhanced color stability as compared with the rawmaterials from which they were obtained.

Tall oil is a mixture of rosin and fatty acids released by acidulationof the black liquor soap skimmed off the black liquorthe concentratedalkaline digestion liquor Washed out of paper pulp in the sulfate orkraft process for manufacture of paper. The crude tall oil is thencommonly fractionally distilled to provide various cuts ranging fromrosin-fatty acid mixtures having a fatty acid content as low as about 1%by weight and rosin content as high as about 99% by weight, usually upto about 90% by weight, to other such mixtures wherein the rosin contentis below about 1% by weight, e.g., 0.3% by weight,

and the fatty acid content is as high as about 99% by weight, e.g.,99.3% by weight.

The term tall oil fractions predominating in fatty acids is employedherein to mean crude, solvent/acidrefined, and distilled tall oilportions as Well as tall oil fractional distillation products, eachhaving a fatty acid content of at least about 50% by Weight, the balancebeing mainly rosin acids in admixture with minor amounts ofunsaponifiable materials of complex chemical constitution. The fattyacids consist mainly of a mixture of oleic, linoleic, conjugatedlinoleic, palmitic, and stearic acids together with lesser amounts ofpalmitoleic, higher molecular weight saturated acids such as arachidic(C behenic (C acids, higher molecular weight unsaturated andpolyunsaturated acids, and low boiling monobasic and dibasic acids.

Preferred tall oils treated according to the present invention are thecommercially available acid/solvent-refined tall oils. Typically, theseare crude tall oils which have been slurried in a hydrocarbon solventsuch as hexane, in a weight ratio of about 40 parts tall oil to 60 partshexane, then treated with about 8-12% by weight of 96-100% concentratedsulfuric acid at about 35 C., and separated. Such refined tall oilsgenerally contain about 50% by weight or more of fatty acids, thebalance being rosin acids, dimerized rosin acids, and unsaponifiablematerials.

Other preferred tall oils are the commercially available tall oilfractions containing a minimum of by weight fatty acids and a maximum of5% by weight rosin acids, the balance being minor amounts of complexunsaponifiable materials.

Light color and color stability are important characteristics forcommercial acceptance of tall oil fatty acids and end products preparedtherefrom. Thus, tall oil fatty acids are conventionally saponified,amidated, aminated, condensed with ethylene oxide and esterified toprovide a host of household and industrial products such as soaps,synthetic detergents, disinfectants, wax emulsions, paper chemicals,coating compositions, epoxy esters and other well known products.

A method commonly employed to improve, i.e., to lighten, the color oftall oil fatty acids involves dry-blending and heating the fatty acidfraction with an adsorbent material such as activated clay. Fullersearth, activated carbon or the like to remove color bodies. The tall oilfatty acid is thereafter separated by filtration and the clay discarded.

To stabilize the resulting improved color, it has become conventional toadd known oxidation inhibitors.

While effective, the prior art methods of bleaching and stabilizing talloil fatty acids have serious deficiencies. Thus, some of the fatty acidswill be adsorbed with color bodies onto the adsorbent materials andsubsequently lost when the adsorbed material is discarded, therebyadding to the expense of the recovered bleached product. Furthermore, asecond treatment with an oxidation inhibitor is often required tostabilize the improved color. This further increases the expense of thefinal product.

An object therefore of the invention is to provide a method of bleachingtall oil fractions predominating in fatty acids while simultaneouslysubstantially stabilizing the improved color.

A further object is to provide a method of bleaching, and substantiallystabilizing the resulting improved color of tall oil fractionspredominating in fatty acids by a simple treatment which avoids fattyacid loss and eliminates or substantially reduces the expense of priorart multi-step methods.

Another object is to provide tall oil fractions predominating in fattyacids having improved color and color stability.

By rosins and rosin compounds is meant abietyl com pounds, i.e.,hydrophenanthrene radical-containing materials, including but notlimited to the following: tall oil rosin, tall oil fractionspredominating in rosin acids, i.e., containing at least about 50% byWeight of rosin acids; wood rosin; and gum rosin; modifications of theseproducts such as hydrogenated rosins, formaldehyde-treated rosins (suchas described in US. Patents 2,934,468 and 3,132,127). Diels-Alderreaction products such as fumarated rosins and maleated rosins;derivatives of such rosins including rosin esters, rosin amines, rosinamides, rosin alcohols, rosin-alkylene oxide adducts; and the numerouswell-known equivalents of the foregoing materials. The term rosinyl, asdefined in US. Patent 2,l54,- 629, is a convenient representation forthe rosins and rosin compounds of the present invention.

Rosin esters include reaction products of rosin and monoand polyhydroxyalcohols'such as methanol, ethanol, butanol, ethylene glycol,pentaerthritol, glycerol, and the like. Among the many well-known rosinamines may be mentioned the products prepared by dehydrating theammonium salt of rosin to the nitrile which is then re duced by hydrogento the amine. Rosin amides are conventionally prepared either bydecomposing ammonium salts of rosin or by reacting rosin with primaryamines. Rosin alcohols are conventionally prepared by reduction of thecorresponding rosin esters. Rosin-alkylene oxide adducts include theknown reaction products of rosin and ethylene oxide and the like.

It is important in many end uses of rosin compounds that the startingmaterial be light-colored and that the color remain stable under normalconditions of use. Thus, rosin compounds are widely employed in themanufacture of paper size, as plasticizers for films such as polyethylene and polypropylene, and for the manufacture of rosins used inpaint and varnish. In these and other end uses the industry desires alight colored product which also exhibits color stability. Hence,industry looks for these properties in the rosin compound intermediatesused to make these products since good color and stability is normallyretained in the end product.

It is known that rosin compounds may be bleached somewhat by heating atelevated temperatures or by treatment with sulfur, sulfur dioxide andsimilar substances. However, the degree of bleaching often is poor andthe treated compounds do not exhibit good color stability. Furthermore,substantial amounts of the treating agent, e.g., sulfur, are oftenrequired, thus adding to the expense of treatment. Distillation andcrystallization are also employed to achieve bleaching but these methodsrequire elaborate apparatus and extended processing time and thussubstantially increase the expense of the treated products. Otherproblems encountered in prior art bleaching methods include retention ofthe odor of the treating agent in the rosin compounds (particularlyobjectionable if sulfur) and tendency to form unsaponifiable materialsduring the treatment.

An object of the present invention is to provide light colored rosincompounds which also exhibit color stability.

A further object is to provide a method of bleaching and stabilizingrosin compounds without substantial effect on other properties of thecompounds, particularly formation of unsaponifiable materials.

A still further object is to provide a low cost method of bleaching andstabilizing rosin compounds which requires only catalytic amounts of atreating agent.

These and other objects, features, and advantages of '7 the inventionwill become more apparent from the description which follows:

The rosin compounds are bleached and stabilized by treatment with minoramounts of a treating compound of Formula I at elevated temperatures fora time sufficient to effect bleaching. Very small amounts of theadditive are effective and may be termed catalytic amounts, e.g., fromabout 0.01% to 1.0%, preferably 0.02% to 0.5%, by weight of the treatingcompound based on the weight of the rosin compound.

The range of temperature and time of treatment will vary depending onthe type of rosin, modified rosin or rosin derivative employed. Littleor no bleaching is observed in the absence of heating or if the rosincompounds are heated in the absence of the treating compound. Normally,the rosin compound is heated in the presence of the treating compound ata temperature in the range of from about 180 C. to 350 C. for up toabout 18 hours, the longer times corresponding to the lower temperaturesand vice versa. A maximum bleach of tall oil rosin is observed in 30minutes in a temperature range of about 250 C. to 275 C. at a treatingcompound concentration of 0.1% and substantially instantaneous bleach isobserved at or above 300 C. The higher temperatures generally promotelighter colors when the treating compound concentration is held constantbut excessive temperatures should be avoided since degradation andexcessive formation of unsaponifiable materials may result therefrom.Optimum bleaching and color stability is obtained for most of the rosincompounds when the same are treated with about 0.1% to 0.5% of thetreating agent at 240 C. to 275 C. for about 30 minutes to one hour.

To avoid oxidation, the treatment is generally conducted under a blanketof inert gas such as nitgrogen, carbon dioxide, steam and the like.

In accordance with the invention the above and other objects areaccomplished 'when the tall oil or fraction thereof or rosin or rosincompound is heated at an effective temperature within the range of aboutl350 C., hereinafter sometimes called a bleaching temperature, in thepresence of effective amounts of a treating com pound of the formulawhere n is an integer from 1 to 3 inclusive, p is an integer from. 0 toand preferably about 5 to 20 inclusive, and

the sum of m and n on each Aryl is: preferably between 1 and5*inclusive. R is a hydrocarbon group, e.g., alkyl, cycloalkyl andsubstituted alkyl, e.g., C -C wherein the substituents are cycloalky],aryl, alkaryl, and the like and desirably contains from 1 to 22 carbonatoms inclusive. Preferred alkyl groups are straight chain secondary andtertiary alkyl groups containing up to 8 carbon atoms inclusive.Preferred Aryl groups are those containing 6 to 18 carbon atomsinclusive typically phenyl,

naphthyl and anthracyl. Typical cycrloalkyl groups contain 3-8 carbonatoms in the ring, e.g., cyclopropyl, cy' clopentyl and cyclohexyl.

In Formula 1 when Aryl is phenyl it will be apparent that when p is 0the sum of m and n on each phenyl ring will not be more than 5 and whenp is 1 or higher the sum of m and n on each phenyl ring will not be morethan 4. It will also be apparent, however, the values for n and m mayrange higher, when Aryl is naphthyl or anthracyl, since when p is O orat least 1 more than 5 or 4 sites, respectively, are available for OHand R substituents. The values for m, n, x and p, except when 0, arepositive, whole numbers.

Included are compounds and position isomers having R groups of mixedcharacter, i.e., the R group or groups on one aryl ring may differ fromthe R group or groups on the other aryl rings; In and 11 may be the sameor different for each aryl ring; and when more than one R group ispresent on an aryl ring, such groups may be identical or different.

The term treating agent" or treating compound," or like term, isintended herein to mean compounds defined by Formula I above.

From the repeating unit of Formula I above it will be seen that theinvention includes not only the use of thiobis compounds (p equals 0)but also higher molecular weight materials, for example, where p is 100or more, provided sumcient sites are available for polymerization, e.g.,the sum of n and m where aryl is phenyl does not exceed 4. The upperlimit of molecular weight is dependent only upon how the compound ismade, e.g., whether the material is sufficiently fluid in the reactionmedium for polymerization to continue, and upon use conditions, e.g.,whether the material can be effectively admixed or blended for goodcontact with the material to be bleached. Ob-

viously, a polymer of such high molecular weight as to be unmanageablytacky or glassy is to be avoided in the practice of the invention. Fromthe viewpoint of economy and ease of preparation and use according tothe invention, preferred treating agents are those which are soluble inthe material treated, e.g., compounds of Formula I wherein p is in therange of to about 20.

As typical and non-limiting examples of the treating agents may bementioned:

Thiobis naphthols, e.g.:

1,1-thiobis( 3-naphthol) 2,2-thiobis(ix-naphthol) 2,2 thiobis phenols,e.g.:

2,2'-thiobis (4-methyl-6-tert.-buty1phenol)2,2'-thiobis(4,6-dimethylphenol) 2,2-thiobis(4,6-di-tert.-butylphenol)2,2-thiobis( 4-ethyl-6-tert.-butylphenol)2,2'-thiobis(4-n-propyl-6-amylphenol) 2,2'thiobis(4-methyl-6-n-octylphenol)2,2-thiobis(4-amyl'6-tert.-octylphenol)2,2'-thiobis(4-methy1-6-n-decylphenol)2,2'-thiobis(4-methyl-6-laurylphenol) 2,2-thiobis [4-methyl-6(1-methylcyclohexyl phenol] 2,2'-thiobis [4-methyl-6-( l-methylbenzylphenol] 2,2'thiobis(4'methylpheno1) 2,2-thiobis(6tert.-butylphenol)2,2'-thiobis(4,6-dilaurylphenol) 2,2'-thiobis(4,6-distearylphenol)3,3'-thiobisphenols, e.g.:

3,3-thiobis-[methyl-6-(1,1,3,3-tetramethylbutyl) phenol] 3,3'-thiobis-(methyl-6-t-dodecylphenol) 3,3-thiobis (pentadecyl-t-butylphenol)4,4'-thiobis penols, e.g.:

Thiobis-polyhydroxy compounds, e.g.:

4,4-thiobis(resorcinol), 5,5'-thiobis(pyrogallol) the diand trithiobisvariants of any of the foregoing, and higher molecular weight materialscorresponding to the repeating unit of any of the foregoing. These andother like compounds are disclosed, for example, in US. Patents2,670,382; 2,670,383; 2,841,619; 3,060,121; 3,069,384; 3,157,517;3,211,794 and Compt. rend. 198, 1791-3 (1934), said disclosures beingincorporated herein by reference.

Particularly preferred are the polyhydroxy compounds such as4,4-thiobis(resorcinol) and 5,5-thiobis(pyrogallol), the so-calledhindered thiobisphenols, e.g., those wherein each aromatic ring issubstituted by one hydroxy group, one bulky group, e.g., secondary ortertiary alkyl group, and one short straight chain (C -C alkyl group,and higher molecular weight compounds wherein p is in the range of 5 to20. Typical of the hindered thiobis phenols are2,2-thiobis(4-methyl-6'tertiarybutylphenol); 4,4-thiobis(6-tertiarybutyl meta cresol); and 4,4'-thiobis- (6'tertiary butyl ortho cresol).Of the thiobisphenols, the first shows best results and it would appearthat as the sulfur atom is shifted away from a position ortho to thehydroxyl and the methyl group is shifted toward the ortho from the paraposition, bleaching efiiciency decreases. Typical of the highermolecular weight compounds is poly[thio-(resorcinol)] wherein p is 6 to9.

The conditions of treatment may be varied over fairly wide ranges andare therefore not particularly critical. Likewise, sequence of admixtureof treating compound and fatty acid fraction is non-critical. Very smallamounts of the additive are effective and may be termed catalyticamounts, e.g., from about 0.01% to 1.0%, preferably 0.02% to 0.5%, byweight of the treating compound based on the weight of the tall oil orrosin or compound thereof. The treating compounds may be employed singlyor in mixtures of two or more.

Good bleaching and color stability of tall oil fatty acid fractions isgenerally achieved by treating them for from about 5 minutes to 5 hoursover a temperature range of about 200 C. to 300 C., the lowertemperature corresponding to the longer time and vice versa. Preferredconditions are a treatment for from about 15 minutes to one hour overabout 240 C. to 275 C., time and temperature being inversely related.Little or no bleaching and colorstabilization is noted below about 200C., and above about 300 C., decomposition and polymerization sets in,particularly in tall oil fractions containing higher proportions offatty acids, e.g., to 99%. The process may be conducted at atmospheric,subor superatmospheric pressure if desired, with correspondingtemperature adustments. Procedures may be batch, semi-continuous orcontinuous.

To avoid oxidation, the treatment is conducted under a blanket of inertgas such as nitrogen, carbon dioxide, steam or the like. Additionaltreatment of tall oil fatty acid fractions to obtain further bleachingand color stability is unnecessary for most end product uses of thefatty acids. However, if desired, bleaching with clay in theconventional manner may be employed as a supplemental treatment tofurther reduce the color. Other stabilizing treatments likewise may beemployed if desired, such as the addition of oxidation inhibitors andthe like.

From the foregoing description, and also from the examples appendedhereto, it will be seen that the present invention is based on thediscovery that tall oil and tall oil ingredients, including particularlyrosins and rosin compounds, can be bleached to lighter and morecolorstable products by heating them in the presence of the phenolsulfide bleaching agents described. The present inventor, jointly withJoseph James McBride, has also discovered that these same phenolsulfides are also disproportionation accelerators or catalysts so thatdisproportionated rosins can be obtained when rosins containing them areheated at from about 250 C. to 350 C. until their abietic acid contentis reduced to less than 15%. It will be understood that this discoveryis not claimed as such herein as it is the claimed subject matter of acopending application Serial No. 579,817 filed Sept. 16, 1966 now PatentNo. 3,377,324 dated Apr. 9, 1968.

The following is a summary of the subject matter of that application.

Under more stringent conditions of treatment, such as heating rosin at300 C. or higher in the presence of catalytic amounts (as definedhereinabove) of treating agent, disproportionation occurs simultaneouslywith bleaching. Generally, disproportionation may be achieved withbleaching when rosin is heated at from about 250 C. to 350 C. for fromabout 1 to 8 hours, preferably from 290 C. to 320 C. for from about 3 to6 hours. A conse quence of disproportionation is greatly improvedresistance of the rosin to oxidation.

For purposes of disproportionation, rosin includes the treated samplesin air at 110 C. (oven) for 1 hour. The color and stability of the feedwere 7 and 7+, respectively.

As compared to the colors of the control after each sampling, maximumbleaching was not more than about two points (7- to 5*) on the colorscale. However, this is considered a good result in the art,particularly in view of the substantial stability of the improved color.

TABLE I Sta- Sta- Sta- Sta- Sta- Sta- Color bll- Color bil- Color bil-Color bil- Color bil- Color bility lty ity ity ity ity tall oil rosin,wood rosin, gum rosin, crude materials and mixtures containing any ofthe foregoing, and in general, abietic acid-containing materials. Rosinmixtures include any of the mixtures of abietic acid with tall oil ortall oil fractions containing various proportions of rosin and fattyacids.

The conditions for disproportionation will be governed by considerationsof economy, i.e., conditions effective for reasonably fast rate ofdisproportionation while avoiding conditions which will causedegradation of the rosin, such as extreme temperatures.

The degree of disproportionation may be controlled as desired and asdictated by the degree of stability required in the end use. Generally,the abietic acid content should be reduced to less than about by weightof the rosin and preferably to the more commercially acceptable level ofless than about 5%, same basis. Reduction of abietic acid content can befollowed during the reaction by sampling and analysis, employing any ofthe procedures known in the art such as the Rubber Reserve (ultraviolet)method or, preferably, by gas-liquid chromatography.

EXAMPLES The above-described features of the invention will be moreparticularly described and illustrated by the following specificexamples, many of which constitute preferred embodiments thereof. Inorder to demonstrate more clearly the application of the inventiveprinciples to tail oil fractions and to rosins and rosin compounds,respectively, the examples dealing with these two classes are arrangedin two separate groups and are numbered consecutively within each group.

Group A.-Bleaching and stabilizing tall oil and tall oil fatty acidsExamples 1-8 The data reported in Table I was obtained under con ditionssubstantially as follows:

To a 1000 ml. reaction flask equipped with agitator, thermometer, andgas inlet tube was charged 500 grams of a commercially available talloil fraction of typical analysis 94.2% mixed saturated and unsaturatedfatty acids, 4.2% rosin acids and 1.6% unsaponifiables. Then was added,2,2-thiobis(4methyl-6-t-butylphenol) in the amounts indicated. Anitrogen atmosphere was then provided and the mixture heated at theindicated temperature for 15 minutes to 2 hours with sampling at 15minute intervals.

The color scales are based on Gardner 1933 standards wherein the lowerthe number the lighter the color. Thus 6 is about tea-colored and 1 ispale yellow. The samples were each tested for color stability (stab) byheating Examples 9-10 The thiobisphenol treatment shows good bleachingwith substantial stability as compared with the feed. As also shown,further bleaching and stability is achieved by subsequent claytreatment. The colors are based on Gardner 1933 standards.

TAB LE 11 9 10 Example Color Stability Color Stability 7- 8- 8 9- 5 ti G7* (3laytrcatod. 2+ 4 3 5 Examples l113 Table III demonstratesbleaching, and stabilization of the resulting improved color, ofsolvent/acid-refined tall oils by treatment at 250 C. under nitrogenwith 0.1% by weight of 2,2' thiobis(4-methyl-6-tbutylphenol) for theindicated times essentially as described in Examples 1-8. The tall oilswere three grades (Examples 11-13) of Facoil solvent refined tall oilsobtained by heating a hexane slurry of crude tall oil with concentratedsulfuric acid and separating the resultant refined oil. The color scaleis the same as Examples 18. The color is improved (lightened) by theacid treatment and further improved by the method of the invention as acomparison of the feed color and stability shows.

Examples l416 Under substantially the same conditions as described inExamples l-13 above, good bleaching and stabilization of the resultingcolor is obtained by treatment of high Group B.Bleaching and stabilizingrosin compounds In all of the examples of this group S-l rosin is talloil rosin conforming to the Naval Stores Act (February 8, 1952) andFederal Specification LLLR6266, Class C (May 27, 1957). S2 rosin issubstantially the same as 3-1 rosin except that it contains less bottomsthan S-l rosin. N rosin is an N-colored S-l tall oil rosin and SH rosinis a heat-treated S-l tall oil rosin.

a suitable reaction vessel equipped with thermometer, inert gas inletand means for agitation. When steam is employed as the inert gas, asuitable condenser is attached. The treating agent is then added to thevessel and heat is applied. The contents are reacted. under an inert gasblanket, such as nitrogen or steam, while maintaining the temperature ata preselected level. Colors are determined following this treatment.Samples are then tested for color stablility after aeration. The samplesare aerated by drawing over them for 10 minutes a volume of air equal to2 milliliters of air per gram of rosin compound which has been heated to180-200 C. under agitation. The vessel containing the treated rosincompound is then closed and agitation continued for 20 minutes at 180 C.in 200 C. Aeration and color sampling is repeated as required.

Table I below shows a number of runs representing batches of severaltypes of rosin compounds treated as above. For comparison, the resultsof treatment with several commercially available antioxidants are shownin section 4 of the table.

TABLE I Treatment Color Table Run Type rosin section (batch) compoundlemp., Weight, Feed After treating After aeration C. Additive percent 1hour 18 hours t 2 3 1 1 X WW. ww-wo, WG-N 2 .1 x Y 3A A 3 .4 X 4A 4A A 4X WW..." WWWCL WG 5 .1 X 3A An-.." 6 .4 4A 2A 7 .1 Y X WW-WG. N 8 WW-WG.WG-N 9 .4 3A X 11 0.1 12 4A 2 13 0.1 5A. 4A 2A 14 0.1 6A 3A 2A 0.05%added at the start of the bleach and 0.05% added after A hour.

In a typical treatment, a rosin compound is charged to Although thenon-thiobisphenol sulfur-containing additives show some bleaching, itwill be noted that additive I gives a better bleach and less color lossafter two aerations than the others. Also notable is the absence ofbleaching with additive II which has the same structure as I except thatsulfur is replaced by CH Table II below shows the effect of treatment,as in the foregoing runs, on analytical values of S2 tall oil rosinsamples. It will be seen that abietic acid content is only slightlyreduced and the other values are negligibly affected if at all. Loss ofabietic acid, i.e., disproportionation, can be minimized by not heatingover 300 C. and by shortening the time of treatment. The analyticmethods are those identified or described in Acintol Tall Oil Products,Arizona Chemical Company, New York, November 1964, pages 2326 exceptthat the percent abietic acid is measured by the Rubber Reserve Methodand hardness is determined by reading the depth of penetration in 0.1mm. units of a standard needle into a solid sample, employing aUniversal Model Penetrometer.

TABLE 11 'lreating Conditions Analyses Run (batch) Additive, Temp. TimeAcid Racine Unsaps, Fatty Specific Hard- S.P., Abietic weight hoursnumber acids percent; acids, rotation uess, C. aci Color percent percentpercent mm. percent- 30 (iced) 175. 6 90. 3. 3 4. 0 +4. 1 0. 79. 5 29. 9X 31 0.1 275 1 174.3 90. 7 4.1 3.1 +15. 5 0.1 83.0 22.1 5A 275 l 174. 890. 7 4. 0 3. 3 +8. 3 0. 1 80.0 26. 7 2A 0.1 200 l 175. 3 90. 3 3. 7 3.9 +11. 9 0. 1 79.0 23. 3 4A 0. 1 240 1 176. 7 89. 4 3.5 5. 5 +7. 4 0.081. 0 27. 9 2A Example 2 treating at 275 C. for /1 hour, a color of Kresulted.

TABLE III S-1 Rosin S-2 Rosin Color WG'I Percent of WG'I Percent ofAdditive I Additive 1 Control 0.1 0.4 Control 0.1 0.4

Feed X X X 1 Aeration. WW. X WW WW... X 2 Aerntions... WW-WG- WW X-WW-WW. WW... X 3 Aerations 'G WG... X-WW. WG WW... X

Example 3.Formaldehyde-treated tall oil rosin Part (A). An S-l tall oilrosin sample was first treated with paraformaldehyde in a conventionalmanner. This product was thereafter bleached as follows:

The formaldehyde-treated rosin was charged to a 1- liter, 3-neck flaskwith attached agitator, thermometer, gas inlet tube, and condenser. Therosin was heated to 260 C. under a nitrogen blanket and2,2-thiobis(4-methyl-6-tbutylphenol) was charged to the flask. Heatingwas continued under steam at 275 C. as indicated with the followingresults:

TABLE IV Color Additive, 1. percent by weight A [tor blcaclnng- Food )5hour 1 hour M-N .\l

Part (B).An S-l tall oil rosin, color WW, was charged to a reactionvessel and heated to 275 C. Then 0.02% by weight of 2,2'thiobis(4 methyl6-t butylphenol) was added and heating was continued for /2 hour. Atthis time the color was Y. The reaction mixture was then cooled over 40minutes to 225 C. Color was then 3A. Paraformaldehyde was thenintroduced at 148 C. and the resulting formaldehyde treated rosin had acolor of K.

Part (C).In another run, paraformaldehyde (1 part to 43 parts tall oilrosin) and 2,2-thiobis(-methyl-6-t-butylphenol), 0.02% by weight, wereadded to 5-1 tall oil rosin, color WW, at 148 C. under pressure. At theend of the formaldehyde treatment, the pressure was vented. A color of 1(dark) resulted. After heating to 275 C., a color of I (light) wasobtained which lightened still further to K when the heating wascontinued at 275 C. for /2. hour. Cooling was applied and, after 45minutes, a temperature of 210 C. was reached. A color of M was obtained.

Part (D).The procedure of Part (A) was repeated with 0.02% of the samethiobisphenol additive except that the additive was charged beforeheating the formaldehydetreated rosin (which had an H color). Themixture was then heated to 275 C. to give a color of I and after Coolingwas then applied and, after minutes, a temperature of 210 C. wasreached. At this time the color was M.

The foregoing runs show that for good bleaching a somewhat extended heattreatment is required in addition to use of the thiobisphenol additive.The duration of heat treatment will vary according to the temperature.The runs also demonstrate that sequence of formaldehyde treatment andthiobisphenol addition are non-critical with respect to Ibleaching,provided the rosin is heated in the presence of the thiobisphenol,although it is preferred to treat with paraforrnaldehyde prior tobleaching.

Example 4.-Fumaric acid adducts of tall oil rosin Part (A).--In a]000-ml.. 3-neck flask equipped with agitator, thermometer, gas inletport and reflux condenser, S-l rosin (color WW) and 4% by weight fumaricacid were heated at -200 C. for 2 hours under nitrogen. A color of Nresulted. The resulting rosin was then bleached 30 minutes at 275 C.with 0.1% 2,2-thiobis(4- methyl-6-t-butylphenol). A color of 3Aresulted. This color was maintained after an additional 30 minutestreatment at 275 C.

Part (B).-In the same equipment as in Part (A), 8-1 rosin (color WW) wasbleached 30 minutes at 275 C. with 0.1% of the same thiobisphenol undernitrogen. A color of 6A resulted. The rosin was then cooled to 200 C.and 4% by weight fumaric acid was added. Treating at 200 C. wascontinued for 2 hours. After this time, a color of 3A was obtained.

Example 5.Maleic anhydride adducts of tall oil rosin,

In the equipment described in Example 4, S-1 rosin and 3.6% by weightmaleic anhydride were heated at 190 C. for 1 hour under nitrogen. Acolor of M resulted. This adduct was then heated 1 hour at 275 C. with0.1% 2,2-thiobis(4-methyl-6-t butylphenol), resulting in WG color.

Examples 6-8 TABLE V Color A biotic Ex. A dditive after acid,

treatment percent 6 2,2-thiobis(4411cthyl-ot-butylphenol). 6A 19. 5 74,4-thiobis(resorcinol) 5A 18. 4 8 2,2-thiobis(4,trdimethylphenol) 4A18. 1

Examples 9-10 Essentially as described in Example 1, S2 rosin wastreated at 275 C. for 1 hour with 0.1% of the thiobisphenol indicated inTable VI to obtain substantial bleaching as shown. The samples werethereafter cooled to 190- 200 C. and aerated as described in Example 1.These tests show good color stability.

TABLE VI Color Ex. Additive Feed After After aeration bleaching(stability) 1 2 3 9 2,2-thlobls(4,6-dimethylphenol) XWW 6A 4A 3A Y 104.4-thiobis(resorcinol) WW 6A A 3A 2A Example 11 about 5 minutes to 5hours, said phenol sulfide being a A. Preparation ofpoly[thio(resorcinol)] To a solution of resorcinol in dibutyl ether isslowly added sulfur dichloride. The temperature is held at 10 15 C. fora half hour after the addition and a polymeric black precipitate forms.Sodium hydroxide solution is then added to dissolve the precipitate andthe dibutyl ether is stripped by steam distillation. The polymer isthereafter precipated by addition of hydrochloric acid to the residualaqueous phase and is collected by filtration as a material medium tan incolor.

The number-average molecular weight is 1250, corresponding to 8repeating units (p equals 6 in Formula I above) and elementalcomposition is in the ranges C 4l.58-46.12%, H 2.973.39%, S21.,3425.06%, ash 324.7%.

B. Bleaching action Essentially as described in Example 1, varioussamples of S-l tall oil rosin were heated at 275 C. under nitrogen for30 minutes with 0.02% by weight of the polymeric product of part A abovewith the good bleaching shown in Table VII below I i TABLE VII Feedcolor Run Product color 'Ihe color of these products was nearly thesame, i.e., product of run 3 was slightly darker than X and the productof run 4 was slightly lighter than WW.

GIT) (HO).. '1 (0B).. (111343-31 {Tr-y) Si]- ]iryl) Rm R p Rm wherein nis an integer from 1 to 3 inclusive, p is an integer from 0 to 100, x is1 to 3 inclusive, the sum of m and n on each Aryl is from 1 to 5inclusive. Aryl is phenyl, naphthyl or anthracyl, and R is a hydrocarbonradical of l to 22 carbon atoms, the heating being at a bleachingtemperature within the range of about 180 C. to about 350 C. andcontinuing the heating at said temperature until a substantiallightening in color of the material is obtained but the abietic acidcontent of any rosin present is not reduced by the heating to less than15%.

2. The method of claim 1 wherein the phenol sulfide is a poly[thio(resorcinol)] wherein p is in the range of 5 to 20.

3. A method of improving both the color and the color stability of atall oil containing at least 50% by weight of fatty acids whichcomprises heating said tall oil at a temperature of about 200 C. to 300C. in the presence of about 0.01% to 1% of a phenol sulfide for compoundof the formula:

wherein n is an integer from 1 to 3, p is an integer from 0 to 100, x is1 to 3, the sum of m and n on each Aryl is from 1 to 5, Aryl is selectedfrom the group consisting of phenyl, naphthyl and anthracyl, and R is ahydrocarbon radical having 1 to 22 carbon atoms.

4. A tall oil product produced by the process of claim 3.

5. A method of bleaching and stabilizing the color of a materialselected from the group consisting of rosin containing atleast 50% ofrosin acids and rosin compounds derived therefrom which comprisesheating said material in the presence of about 0.01% to 1% of a phenolsulfide of the formula:

wherein n is an integer from 1 to 3 inclusive, p is an integer from 0 to100, x is 1 to 3 inclusive, the sum of m and n on each Aryl is from 1 to5 inclusive, Aryl is phenyl, naphthyl or anthracyl, and. R is ahydrocarbon radical of 1 to 22 carbon atoms, the heating being at about180 C. to 350 C. and for a time ranging from instantaneous to 18 hoursand such that a substantial lightening in color of the material. isobtained but the abietic acid content is not reduced by the heating toless than 15%.

6. The method of claim 5 wherein the material is a member of the groupconsisting of wood rosin, gum rosin and tall oil rosin.

7. A bleached member of the group consisting of wood rosin, gum rosinand tall oil rosin, said member being produced by the process of claim6.

8. A method of treating a rosin comprising heating said rosin at atemperature of about 180 C. to 350 C. for about 1 to 8 hours in thepresence of about 0.01% to 1% of a phenol sulfide of the formula:

wherein n is an integer from 1 to 3; p is an integer from 0 to x is anumber from 1 to 3; the sum of m and n on each Aryl is from 1 to 5; Arylis selected from the group consisting of phenyl, naphthyl, andanthracyl; and R is a hydorcarbon radical containing from 1 to 22 carbonatoms, the heating being for a time such that a substantial lighteningof the material is obtained but the abietic acid content is not reducedby the heating to less than 15 9. The product produced by the process ofclaim 8.

10. The process of claim 8 wherein said phenol sulfide ispoly[thio(resorcinol)] wherein p is in the range of 5 to 20.

11. The process of claim 8 wherein said phenol sulfide is4,4'-thio-bis-(resorcinol).

12. The process of claim 8 wherein said phenol sulfide is2,2'-thio-bis-(4-methyl-6-t-butyl-phenol).

15 13. A method of improving both the color and the color stability of atall oil containing at least 50% by weight of fatty acids whichcomprises heating said tall oil at 200 C. to 300 C. under a blanket ofinert gas and at substantially atmospheric pressure in the presence ofan effective amount, within the range of about 0.01% to 1%, of a phenolsulfide for a time, within the range of about 5 minutes to 5 hours,until a substantial lightening of its color is obtained, said phenolsulfide being a compound of the formula Rm Rm where n is an integer from1 to 3 inclusive, p is an integer from 0 to 100, x is 1 to 3, the sum ofm and n on each Aryl is from 1 to 5 inclusive, Aryl is phenyl, naphthylor anthracyl and R is a hydrocarbon radical of 1-22 carbon atoms.

14. A method according to claim 13 in which the tall Oil is a commercialfraction containing about 94.2% mixed saturated and unsaturated fattyacids, about 4.2% rosin acids and 1.6% unsaponifiables, the phenolsulfide is 2,2'-thiobis(4-methyl-6-t-butylphenol), and the heating is atabout 240 C. to 275 C. for from about 15 minutes to two hours.

16 References Cited UNITED STATES PATENTS 3,157,517 11/1964 Tholstrup etal 99--163 3,211,794 12/1965 Cofiield 260609 3,253,042 5/1966 Worrel260-608 3,281,473 10/1966 OShea 260- 609 FOREIGN PATENTS 512,304 4/ 1955Canada. 294,526 9/1929 Great Britain.

OTHER REFERENCES DONALD E. CZAJA, Primary Examiner. FRED E. MCKELVEY,Assistant Examiner.

U.S. Cl. X.R. l62--180; 26027, 98, 398.5, 609

